Nijuu Mensou no Musume EP17 - Giant Dark Room

Chiko goes with Kouhei, leaving a note on her bed for Tome that she will "definitely be back". Ken sees Chiko in the car and follows but is attacked by a girl who is very much like the boy who attacked Chiko last time. It doesn't seem she can be wounded as she is hit by a metal object of some sort on the road and has no injuries from it. Ken lights the girl on fire, destroying his motorcycle, yet to his surprise the girl has not a scratch and comes at him again. This time, Dr. Kayami intercepts it (the girl seems to be a more stable experiment much like Dr. Kayami herself). They escape. Meanwhile, Chiko and Kouhei have gone underground to a secret laboratory where Kouhei is trying to create the "Fourth Form of Water" which is light. Chiko has connected this research to the poem and refuses to help Kouhei. He shows her that he has Shunka captive and will use her in an experiment if she does not help him. So she give him what he wants, only to be deceived. Twenty Faces shows up and rescues Shunka before facing Kouhei.